(added few years ago!)

It has been a mystery for many that why some people use left hand (about 10 per cent on average). Now, two researchers of North-western University have reported that a high degree of cooperation was the major cause behind this speciality.

It is interesting to mention here that in the past people used to think lefthanders as if they were some kind of evil creature. However, the study described it the other way round.

The balance between cooperation and competition in human evolution was the reason that some people in the world were lefthanders, the researchers noted, describing the process through a mathematical model.

“The more social the animal—where cooperation is highly valued—the more the general population will trend toward one side,” said Abrams, an assistant professor of engineering sciences and applied mathematics at the McCormick School of Engineering and Applied Science.

“The most important factor for an efficient society is a high degree of cooperation. In humans, this has resulted in a right-handed majority.”

If societies were entirely cooperative everyone would be same-handed, Abrams revealed this interesting fact.

The model helps to explain our right-handed world now and historically: the 90-10 right-handed to left-handed ratio has remained the same for more than 5,000 years.

“The accuracy of our model’s predictions when applied to sports data supports the idea that we are seeing the same effect in human society,” Abrams said.

“As computers and simulation become more widespread in science, it remains important to create understandable mathematical models of the phenomena that interest us, such as the left-handed minority,” Abrams said.

“By discarding unnecessary elements, these simple models can give us insight into the most important aspects of a problem, sometimes even shedding light on things seemingly outside the domain of math,” Abrams added.

The results have been published in The Journal of the Royal Society Interface.